Antenna arrangement

ABSTRACT

An antenna arrangement includes a first portion and a second portion, each portion being arranged spaced apart and on first and second sides of at least one carrier structure. Each of said first and second portions includes at least one antenna element. The antenna elements of each antenna portion are electrically connected and the antenna element of said first portion is arranged to transmit an incident electromagnetic radiation on said first side of said carrier in form of an electrical signal to the antenna element of said second portion on said second side of said carrier. The antenna element of said second portion is arranged to transform and radiate the electrical signal from the second side of the carrier. Each antenna element comprises a thin layer of a conductive coating arranged on at least part of surface of said carrier.

TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to an antenna arrangement,preferably a passive antenna arrangement and specially an antennaarrangement of the type that comprises a first portion and a secondportion. Each portion being arranged spaced apart and on first andsecond sides of at least one carrier structure. Each of said first andsecond portions comprising at least one antenna element. The antennaelements of each antenna portion is electrically connected and theantenna element of said first portion is arranged to transmit anincident electromagnetic radiation on said first side of said carrier inform of an electrical signal to the antenna element of said secondportion on said second side of said carrier, which antenna element ofsaid second portion is arranged to transform and radiate the electricalsignal from the second side of the carrier.

[0002] The invention also relates to a method of manufacturing theantenna arrangement.

BACKGROUND OF THE INVENTION

[0003] Excellent coverage indoors, is usually a problem for satellitetransmissions and telecommunications. In particular, the growth of thetelecommunications and especially cellular telecommunications hasincreased the need for smaller and more frequent cells, e.g. in GSMnetworks. The cells comprise base station antennas, which generally areprovided on roofs, house fronts, masts etc., resulting in an unaestheticappearance of the urban environment.

[0004] Thus, there is a need for a new type of antenna that fulfils therequirements for an effective antenna, provide invisibility and allowbetter coverage indoors. The antenna according to the invention dose notacquires any substantial space.

[0005] In JP 11 122023, the problem to be solved is to utilize thewindow glass of a building as a low altitude antenna installation methodand to install a small-sized radio equipment indoors to be connected toindoor communication line and power supply line. Hence, an antennatransparent film provided with an antenna radiation circuit and acoupling element for feeding power is placed on the outer surface of thewindow glass. A reflector film provided with a circuit equivalent to areflector on antenna characteristics and a coupling element for feedingpower is s arranged, corresponding to the antenna transparent film on aninner surface side. The coupling element for feeding the power iscapacitively coupled with the coupling element and feeds the power tothis antenna. The coupling element for feeding the power and the radioequipment are connected through a feeder.

[0006] EP 608 180 relates to windows, especially compound windows,consisting of at least one sheet of a rigid material, permanentlyincluding a surface antenna consisting of at least one microstripseparated from an earth plane by a dielectric. These windows includingsuch an antenna are used for reception and transmission of frequencieshigher than 1 GHz, and preferably for the frequency bands 5795-5815 MHz,63-64 GHz and 74-77 GHz.

[0007] Other less relevant windshield antennas are also known; see forexample U.S. Pat. No. 5,714,959, U.S. Pat. No. 5,926,141, DE 4 420 903and JP 8 242 115.

[0008] In EP 431 640 A2, a mobile cellular antenna system is described,which includes an auxiliary antenna that is coupled to a radiator on theexterior of a vehicle. This arrangement permits users or portable ortransportable cellular telephones with built-in antennas to gaintransmission and reception advantage from the exterior antenna whileoperating from within the passenger compartment.

[0009] European Patent Publication No. 429 203 relates to an antennasystem for a vehicle and particularly for a radiotelephone. The systemcomprises a whip antenna fastened to the outside of the vehicle andreceiving and/or transmitting signals. The antenna is in galvaniccommunication with the interior of the vehicle. Inside the vehicle thereis an internal whip antenna connected galvanically to the externalantenna. The radiotelephone includes a separate antenna of its own.

[0010] According to JP 61-285219, antennas are arranged on a base andare adhered onto an inner face of a window panel of floors or the like.Matching circuits are made of the film base and connected to a feeder.When a carrier of a sub set in one floor makes a call, a radio wave isradiated from an antenna to a space in the room. The radio wave isreceived by a first antenna, fed to the second antenna via a feeder andthe matching device and radiated into the second floor as the radiowave. The radio wave is received by a second antenna of a main set, to aspeaker or a telephone line, allowing the call with an external line.

[0011] JP 10-378352 describes an antenna device, in which radio wavesreceived by a first antenna are guided through a cable, and the radiowaves are transmitted from a second antenna so that radio waves can besatisfactorily transmitted and received in a fixed range within severaltens of centimeters in the vicinity of the second antenna.

SUMMARY OF THE INVENTION

[0012] Thus, the main object of the present invention is to provide anantenna, especially a passive antenna that provides better transmissioninto and out of an enclosed volume or a compartment.

[0013] Another object of the present invention is to provide a novelmethod of manufacturing an antenna arrangement according to theinvention, especially on silicon-based carriers.

[0014] Therefore, in the initially mentioned antenna arrangement eachantenna element comprises a thin layer of a conductive coating arrangedon at least part of surface of said carrier.

[0015] In the most preferred embodiment, said carrier structurecomprises at least two glasses in a two-glass window and the antennaelements are arranged on the surfaces of each glass. It is possible tocontrol the radiation by providing each antenna element on each glasswith different characteristics.

[0016] In another embodiment said carrier structure is glasses of athree-glass window. In this case, an intermediate glass is provided witha ground plane and inner and outer glasses are arranged with antennaelements.

[0017] Each antenna element can have a pattern, which can be adapted toa desired frequency. Also, the distance between the antenna parts isadapted such that a desired performance within an especial frequencyband(s) is obtained.

[0018] The function of the antenna can be controlled by designing anexternally arranged antenna element to direct an antenna lobe to aradiation source.

[0019] According to one aspect of the invention, the antenna elementsare formed as a group antenna for providing increased amplification.

[0020] According to one embodiment, the antenna arrangement constitutesa Planar Inverted-F Antenna (PIFA), wherein one antenna element at oneside of said carrier is arranged as a radiating element and anotherelement at the other side of the carrier is arranged as a ground plane.This arrangement allows for powerful but yet simple antennas and alsofor multi-band antennas. In one embodiment the thin conductive layer isarranged as a microstrip. Specially but not exclusively, in windowapplications, at least one of said elements is substantially lightpreamble.

[0021] According to the invention a method of manufacturing an antennaelement on a transparent carrier is provided, which comprises arranginga light permeable and conductive coating on said carrier, and arranginga galvanic connection to said coating. The coating is arranged with ashape or size by selective coating and/or by cutting out section bymeans of a laser beam. The coating can be provided through spraying orsputtering.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In the following, the invention will be further described in anon-limiting way with reference to the accompanying drawings in which:

[0023]FIG. 1 is a schematic perspective view of an antenna arrangementaccording to the first aspect of the invention,

[0024]FIG. 2 is a schematic perspective view of an antenna arrangementaccording to the second aspect of the invention,

[0025]FIG. 3 is a schematic cross-sectional view of an alternativeembodiment according to the second aspect of the invention,

[0026]FIG. 4 is a schematic cross-sectional view of an antennaarrangement according to the third aspect of the invention,

[0027]FIG. 5 is a schematic perspective view of an antenna arrangementaccording to the fourth aspect of the invention, and

[0028]FIG. 6 is a schematic perspective view of a second embodiment ofthe antenna arrangement according to the first aspect of the invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] A simple design of the antenna arrangement 10, according to thepresent invention, is illustrated in FIG. 1. The antenna arrangement 10consists of two parts, a first part 11 and a second part 12 arranged onopposite sides of a carrier 13. Each antenna part 11 and 12 comprisesantenna elements, in this case configured as microstrips 111, 112 and121, 122, respectively. The microstrips of each part are interconnectedand each part is coupled through a connection 14. Thus, the antennafunctions as a link antenna. The incoming radiation, e.g. received byelements 111 and 112 of the first part 11, is converted into electricalsignals and transmitted to the second part 12, elements 121 and 122 ofwhich are arranged to radiate on the other side of the carrier 13. Theinterconnection between the elements can be provided as a galvanic,capacitive or inductive connection. The antenna elements are resonant ata certain frequency. The elements are not supplied with external powerbut help to conduct the radiation past the carrier. The elements of eachpart have same shape. The advantage of using microstrip elements will beevident when describing one preferred manufacturing method here below.

[0030] The carrier can be a panel on a building, glass, signboard, etc.,which usually deteriorates the passage of electromagnetic radiation. Inthe case where a wall panel of a building or a window glass is used asthe carrier, the antenna links the radiation into and outside thebuilding and provides for better indoor reception.

[0031] In the most preferred embodiment, as illustrated in FIG. 2, theantenna arrangement 20, comprising two parts, a first part 21 and asecond part 22, is arranged on opposite sides of two carriers 23 a and23 b made of glass or similar material. As in the forgoing example 10,each antenna part 21 and 22 comprises antenna elements 211, 212 and 221,222, respectively. Each part is coupled through a connection 24.

[0032] Preferably, the glasses are part of a window, in particular atwo-glass window. Advantageously, one part of the antenna arrangementcan be arranged on the inner surface of one of the glasses, i.e. betweenthe glasses. It is also possible to arrange the antenna on a three-glasswindow etc.

[0033] A cut through a part of a two-glass window is illustrated in FIG.3. The glasses 33 a and 33 b are arranged in a frame 37, enabling adistinct distance between the glasses. In this case, the antenna element311 belonging to one antenna part 31 of the antenna arrangement 30 isplaced on the outer surface of the outer glass 33 a and the antennaelement 321 belonging to the other antenna part 32 is arranged on theouter surface of the inner glass 33 b, i.e. in the space between theglasses. Moreover, the antenna elements have different sizes (or shapes)to be able to alter radiation characteristics. The antenna parts areinter-connected through a connection 34, which can comprise a conductivepaste, a conductor or the like. If a three-glass window is used, theintermediate glass can be provided with a third layer of conductivecoating arranged as a ground plane for the purpose of screening betweenthe antenna parts.

[0034] The antenna elements may also be arranged on different sides of acarrier as illustrated in FIG. 6. In this example, the carrier 63 iscubical and antenna elements 61 and 62 are arranged on two adjacentsides. Thus, the arrangement redirects the radiation.

[0035] The advantageous result of above described antennas is that,particularly in urban environments, the effect of the base stationtransmitters can be reduced as the power required for penetratingthrough obstacles, such as windows and walls will be reduced. Also, thereceiving features for satellite transmissions are improved as the wallsor the like, surrounding a compartment or room, will no longer besignificant obstacles a.

[0036] The antenna element material can consist of any conductivematerial. However, the antenna elements applied on a window glass shouldbe made of a thin and light preamble conductive film. The antennaelement pattern can be adapted to a determined frequency. Also, thedistance between the antenna parts, i.e. the distance between the glasssurfaces can be adapted such that the desired performance can beobtained. Parameters like the size, form and distance between theantenna elements are frequency specific, i.e. the received and radiatedfrequencies can be specified and changed by changing the mentionedparameters.

[0037] This passive antenna design is suitable for high frequencyapplications, where the glass normally suppresses the radiation. Theexternal antenna elements can be deigned to direct the antenna lobe,e.g. towards a base station antenna. The antenna elements can also beformed as a group antenna, which provides increased amplificationresulting in less required transmission power from the base station andan indoor terminal and allowing better coverage.

[0038] As mentioned above, when a window is used as the supportstructure for the antenna, it is desired that the antenna elements donot deteriorate the light permeability (thus the function of thewindow). In the most preferred embodiment of the invention, the antennaelements are provided as a thin, conductive, light preamble coating.Preferably, the coating is applied through sputtering, spraying or thelike on the glasses. A termination paste can be applied on the edges ofthe glass or at the inter-connection positions. Then the paste is curedthrough heating. The conductive coating may consist of any conductivematerial, preferably silver, gold, stannic oxide or the like can beused. The antenna elements can be shaped (size and/or form) throughselective coating or cut out by means of a laser beam. The coating canbe provided with a protective layer, e.g. by providing a glass laminate.

[0039] The above-described manufacturing method enables the arrangementof active antennas on a glass or silicon carrier as well. FIG. 4illustrates a cut through a three-glass window 48 comprising a frame 47framing three glasses 43 a-43 c. The antenna arrangement 40 comprises afirst portion 41 and a second portion 42. The first portion 41 comprisesat least one antenna element 411 arranged as the radiator on the innersurface of the intermediate glass 43 b and the second portion 42comprises a ground plane 421 arranged on outer surface of the innerglass 43 c. The radiator 411 is connected to a transceiver circuit 49 ofa communication device (not shown). Thus, the antenna arrangementfunctions as an active antenna converting input signal from thetransceiver circuit to electromagnetic radiation and incidentelectromagnetic radiation to electrical signals.

[0040] Another example of the active antenna is shown in FIG. 5. Theantenna arrangement 50 is a ground plane dependent antenna, such as aPIFA (Planar Inverted-F Antenna). A first glass 53 a is provided with aconductive coating acting as the radiator element 51 and the secondglass 53 b is provided with a ground plane. The conductive layer isarranged with a non-conductive gap 513, which allows the antenna tofunction as a dual band antenna. The gap is produced by selectivesputtering/spraying or cut out by means of a laser beam. The radiator isconnected to a transceiver circuit 59 by means of feed connection and tothe ground by means of a ground connection.

[0041] The invention is not limited to the shown embodiments but can bevaried in a number of ways without departing from the scope of theappended claims and the arrangement and the method can be implemented invarious ways depending on application, functional units, needs andrequirements etc. Thus, the shape and number of the radiators and theirposition is not limited to the illustrated examples and otheralternatives can occur

What we claim is:
 1. An antenna arrangement comprising a first portionand a second portion, each portion being arranged spaced apart and onfirst and second sides of at least one carrier structure, each of saidfirst and second portions comprising at least one antenna element, saidantenna elements of each antenna portion being electrically connectedand the antenna element of said first portion is arranged to transmit anincident electromagnetic radiation on said first side of said carrier inform of an electrical signal to the antenna element of said secondportion on said second side of said carrier, which antenna element ofsaid second portion is arranged to transform and radiate the electricalsignal from the second side of the carrier, wherein each antenna elementcomprises a thin layer of a conductive coating arranged on at least partof surface of said carrier.
 2. The antenna arrangement of claim 1,wherein said carrier structure comprises at least two glasses in atwo-glass window.
 3. The antenna arrangement of claim 2, wherein saidantenna elements are arranged on the surfaces of each glass.
 4. Theantenna arrangement of claim 2, wherein each antenna element on eachglass has different characteristics.
 5. The antenna arrangement of claim1, wherein said carrier structure is glasses of a three-glass window. 6.The antenna arrangement of claim 5, wherein an intermediate glass isprovided with a ground plane and inner and outer glasses are arrangedwith antenna elements.
 7. The antenna arrangement according claim 6,wherein each antenna element has a pattern, which can be adapted to adesired frequency.
 8. The antenna arrangement according to claim 1,wherein said distance between the antenna parts is adapted such that adesired performance for a special frequency(ies) is obtained.
 9. Theantenna arrangement according to claim 1, wherein an externally arrangedantenna element is designed to direct an antenna lobe to a radiationsource
 10. The antenna arrangement according to claim 2, wherein theantenna elements are formed as a group antenna for providing increasedamplification.
 11. The antenna arrangement according to claim 1, whereinsaid antenna arrangement constitutes a Planar Inverted-F Antenna (PIFA),wherein one antenna element at one side of said carrier is arranged as aradiating element (51) and another element at the other side of thecarrier is arranged as a ground plane.
 12. The antenna arrangementaccording to claim 1, wherein said thin conductive layer is arranged asa microstrip.
 13. The antenna arrangement according to claim 1, whereinat least one of said elements is substantially light preamble.
 14. Amethod of manufacturing an antenna arrangement comprising a firstportion and a second portion, each portion being arranged spaced apartand on first and second sides of at least one carrier structure, each ofsaid first and second portions comprising at least one antenna element,said antenna elements of each antenna portion being electricallyconnected and the antenna element of said first portion is arranged totransmit an incident electromagnetic radiation on said first side ofsaid carrier in form of an electrical signal to the antenna element ofsaid second portion on said second side of said carrier, which antennaelement of said second portion is arranged to transform and radiate theelectrical signal from the second side of the carrier, wherein eachantenna element comprises a thin layer of a conductive coating, themethod comprising arranging a substantially light permeable andconductive coating on at least part of said carrier, and arranging agalvanic connection to said coating.
 15. The method of claim 14, whereinsaid coating is arranged with a shape or size by selective coating. 16.The method of claim 14, wherein said coating is arranged with a shape orsize by cutting out a section by means of a laser beam.
 17. The methodaccording to claim 16, wherein said coating is provided through sprayingor sputtering.